Methods, apparatus and system for providing source-drain epitaxy layer with lateral over-growth suppression

ABSTRACT

At least one method, apparatus and system disclosed herein for suppressing over-growth of epitaxial layer formed on fins of fin field effect transistor (finFET) to prevent shorts between fins of separate finFET devices. A set of fins of a first transistor is formed. The set of fins comprises a first outer fin, an inner fin, and a second outer fin. An oxide deposition process is performed for depositing an oxide material upon the set of fins. A first recess process is performed for removing a portion of oxide material. This leaves a portion of the oxide material remaining on the inside walls of the first and second outer fins. A spacer nitride deposition process is performed. A spacer nitride removal process is performed, leaving spacer nitride material at the outer walls of the first and second outer fins. A second recess process is performed for removing the oxide material from the inside walls of the first and second outer fins. An epitaxial layer deposition processed upon the set of fins. A portion of the lateral over-growth of epitaxial layer on the outer walls of the first and second outer fins is suppressed by the spacer nitride material.

BACKGROUND OF THE INVENTION

Field of the Invention

Generally, the present disclosure relates to the manufacture ofsophisticated semiconductor devices, and, more specifically, to variousmethods for fabricating high performance finFET devices using epitaxiallayer with over-growth suppression.

Description of the Related Art

The fabrication of advanced integrated circuits, such as CPU's, storagedevices, ASIC's (application specific integrated circuits) and the like,requires the formation of a large number of circuit elements in a givenchip area according to a specified circuit layout, wherein so-calledmetal oxide field effect transistors (MOSFETs or FETs) represent oneimportant type of circuit element that substantially determinesperformance of the integrated circuits. A FET is a device that typicallyincludes a source region, a drain region, a channel region that ispositioned between the source region and the drain region, and a gateelectrode positioned above the channel region. Current flow through theFET is controlled by controlling the voltage applied to the gateelectrode. If a voltage that is less than the threshold voltage of thedevice is applied to the gate electrode, then there is no current flowthrough the device (ignoring undesirable leakage currents, which arerelatively small). However, when a voltage that is equal to or greaterthan the threshold voltage of the device is applied to the gateelectrode, the channel region becomes conductive, and electrical currentis permitted to flow between the source region and the drain regionthrough the conductive channel region.

To improve the operating speed of FETs, and to increase the density ofFETs on an integrated circuit device, device designers have greatlyreduced the physical size of FETs over the years. More specifically, thechannel length of FETs has been significantly decreased, which hasresulted in improving the switching speed of FETs. However, decreasingthe channel length of a FET also decreases the distance between thesource region and the drain region. In some cases, this decrease in theseparation between the source and the drain makes it difficult toefficiently inhibit the electrical potential of the channel from beingadversely affected by the electrical potential of the drain. This issometimes referred to as a so-called short channel effect, wherein thecharacteristic of the FET as an active switch is degraded.

In contrast to a planar FET, which has a planar structure, there areso-called 3D devices, such as an illustrative FinFET device, which is a3-dimensional structure. More specifically, in a FinFET, a generallyvertically positioned, fin-shaped active area is formed and a gateelectrode encloses both of the sides and the upper surface of thefin-shaped active area to form a tri-gate structure so as to use achannel having a 3-dimensional structure instead of a planar structure.In some cases, an insulating cap layer, e.g., silicon nitride, ispositioned at the top of the fin and the FinFET device only has adual-gate structure.

FinFET designs use “fins” that may be formed on the surface of asemiconductor wafer using selective-etching processes. The fins may beused to form a raised channel between the gate and the source and drainof a transistor. The gate is then deposited such that it wraps aroundthe fin to form a trigate structure. Since the channel is extremelythin, the gate would generally have a greater control over the carrierswithin. However, when the transistor is switched on, the shape of thechannel may limit the current flow. Therefore, multiple fins may be usedin parallel to provide greater current flow for increased drivestrength.

FIG. 1 illustrates a stylized cross-sectional depiction of astate-of-the-art FinFET device. A FinFET device 100 illustrated in FIG.1 comprises a plurality of “fins” 110. The semiconductor device may beposition to a vertical orientation, creating one or more fins 110. Thesource and drain of the FinFET are placed horizontally along the fin. Ahigh-k metal gate 120 wraps over the fin, covering it on three sides.The gate 120 defines the length of the FinFET device. The current flowoccurs along an orthogonal crystal plane in a direction parallel to theplane of the semiconductor wafer. The electrically significant height ofthe fin (labeled H) is typically determined by the amount of oxiderecess in the fin reveal step and hence is constant for all fins 110.

The thickness of the fin (labeled T_(fi)) determines the short channelbehavior of the transistor device and is usually small in comparisonwith the height H of the fin 110. The pitch (labeled P) of the fins isdetermined by lithographic constraints and dictates the wafer area toimplement the desired device width. A small value of the pitch P and alarge value of the height H enable a better packing of the devices persquare area resulting in a denser design, or more efficient use ofsilicon wafer area.

The scaling down of integrated circuits coupled with higher performancerequirements for these circuits have prompted an increased interest infinFETs. FinFETs generally have the increased channel widths, whichincludes channel portions formed on the sidewalls and top portions ofthe fins. Since drive currents of the finFETs are proportional to thechannel widths, finFETs generally display increase drive currentcapabilities.

Typically, in order to increase performance capability of devices,designers had proposed increasing the height of the fins in state of theart finFETs. Increasing the height of the fins would increases wouldincrease the current drive of the finFET, thereby increasing performanceof the finFETs. However, the greater height would cause the device to belarger in size, leading to larger sized integrated circuit made from thefinFETs.

Another state of the art solution offered by designers includes growingan epitaxial (EPI) layer at the top of source/drain fins of finFETs.FIG. 2 illustrates a stylized depiction of a cross-sectional view of atypical growth of EIP layer at the top of source/drain fins of a typicalfinFET. A plurality of fins 220 a, 220 b, 220 c are formed in a shallowtrench isolation (STI) layer 210 for manufacturing finFETs 200.

To increase the current drive of the finFETs 200, the source-drain fins220, epitaxial (EPI) layers 230 are formed on the fins 220. One problemassociated with the state of the art includes the fact that as the EIPlayers 230 are formed on the fins 220, lateral growth may cause a shortto occur between fins 210 b and 210 c, which are fins of differentfinFET devices. Although the connection of the EPI layer 230 betweenfins 220 a and 220 b are not problematic since they belong to the samedevice, the short between the EPI layer between the fins 220 b and 220 care problematic since they are respectively of different devices.Therefore, this process is not possible in many designs, such as designsthat contain tight chip design rules and densely arranged devices and/orfins. Some designers have attempted to suppress lateral EPI growth toaddress this problem. However, this approach limits the EPI layers insuch a manner that high leakage currents may be induced because contactsilicide can be formed too close to the channel.

FIG. 3 illustrates a stylized depiction of a top view layout of atypical finFET device. FIG. 3 illustrates two gate regions 310 a, 310 bof a finFET device 300. FIG. 3 shows source-drain fins 320. EPI growth330 may be formed at the top of the fins 320 to enhance current drive.However, as shown in the portion above the gate 310 b, a source-drainbridge 350 may occur due to the over-growth of the EPI layer 330,causing a short upon the end of the gate 310 b. This short may causevarious errors and operational problems.

The present disclosure may address and/or at least reduce one or more ofthe problems identified above.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an exhaustive overview of the invention. It is notintended to identify key or critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome concepts in a simplified form as a prelude to the more detaileddescription that is discussed later.

Generally, the present disclosure is directed to various methods,apparatus and system for suppressing over-growth of epitaxial layerformed on fins of fin field effect transistor (finFET) to prevent shortsbetween fins of separate finFET devices. A set of fins of a firsttransistor is formed. The set of fins comprises a first outer fin, aninner fin, and a second outer fin. An oxide deposition process isperformed for depositing an oxide material upon the set of fins. A firstrecess process is performed for removing a portion of oxide material.This leaves a portion of the oxide material remaining on the insidewalls of the first and second outer fins. A spacer nitride depositionprocess is performed. A spacer nitride removal process is performed,leaving spacer nitride material at the outer walls of the first andsecond outer fins. A second recess process is performed for removing theoxide material from the inside walls of the first and second outer fins.An epitaxial layer deposition processed upon the set of fins. A portionof the lateral over-growth of epitaxial layer on the outer walls of thefirst and second outer fins is suppressed by the spacer nitridematerial.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numerals identify like elements, and in which:

FIG. 1 illustrates a stylized cross-sectional depiction of astate-of-the-art FinFET device;

FIG. 2 illustrates a stylized depiction of a cross-sectional view of atypical growth of EIP layer at the top of source/drain fins of a typicalfinFET;

FIG. 3 illustrates a stylized depiction of a top view layout of atypical finFET device herein;

FIG. 4 a flowchart depiction of a method for forming EPI layer onsource-drain fins for finFET devices while controlling laterover-growth, in accordance with embodiments herein;

FIG. 5-6 illustrates various stylized diagrams relating to forming afinFET device, in accordance with embodiments herein;

FIG. 7 illustrates a stylized cross-sectional view of a set of finFETs(device 700) under manufacture, in accordance with embodiments herein;

FIG. 8 illustrates a stylized cross-sectional 90 degree rotated view ofthe set of finFETs of FIG. 7, in accordance with embodiments herein;

FIG. 9 illustrates a stylized cross-sectional view of a set of thefinFETs undergoing an oxide deposition process, in accordance withembodiments herein;

FIG. 10 illustrates a stylized cross-sectional 90 degree rotated view ofthe set of finFETs of FIG. 9, in accordance with embodiments herein;

FIG. 11 illustrates a stylized cross-sectional view of a set of thefinFETs undergoing an oxide removal process, in accordance withembodiments herein;

FIG. 12 illustrates a stylized cross-sectional 90 degree rotated view ofthe set of finFETs of FIG. 11, in accordance with embodiments herein;

FIG. 13 illustrates a stylized cross-sectional view of a set of thefinFETs undergoing an nitride deposition process, in accordance withembodiments herein;

FIG. 14 illustrates a stylized cross-sectional 90 degree rotated view ofthe set of finFETs of FIG. 13, in accordance with embodiments herein;

FIG. 15 illustrates a stylized cross-sectional view of a set of thefinFETs undergoing an spacer nitride removal, in accordance withembodiments herein;

FIG. 16 illustrates a stylized cross-sectional 90 degree rotated view ofthe set of finFETs of FIG. 15, in accordance with embodiments herein;

FIG. 17 illustrates a stylized cross-sectional view of a set of thefinFETs undergoing an EPI fill oxide recess process, in accordance withembodiments herein;

FIG. 18 illustrates a stylized cross-sectional 90 degree rotated view ofthe set of finFETs of FIG. 17, in accordance with embodiments herein;

FIG. 19 illustrates a stylized cross-sectional view of a set of thefinFETs undergoing an EPI deposition process, in accordance withembodiments herein;

FIG. 20 illustrates a stylized cross-sectional 90 degree rotated view ofthe set of finFETs of FIG. 19, in accordance with embodiments herein;and

FIG. 21 illustrates a stylized depiction of a system for fabricating asemiconductor device package comprising finFET devices, in accordancewith embodiments herein.

While the subject matter disclosed herein is susceptible to variousmodifications and alternative forms, specific embodiments thereof havebeen shown by way of example in the drawings and are herein described indetail. It should be understood, however, that the description herein ofspecific embodiments is not intended to limit the invention to theparticular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Various illustrative embodiments of the invention are described below.In the interest of clarity, not all features of an actual implementationare described in this specification. It will of course be appreciatedthat in the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

The present subject matter will now be described with reference to theattached figures. Various structures, systems and devices areschematically depicted in the drawings for purposes of explanation onlyand so as to not obscure the present disclosure with details that arewell known to those skilled in the art. Nevertheless, the attacheddrawings are included to describe and explain illustrative examples ofthe present disclosure. The words and phrases used herein should beunderstood and interpreted to have a meaning consistent with theunderstanding of those words and phrases by those skilled in therelevant art. No special definition of a term or phrase, i.e., adefinition that is different from the ordinary and customary meaning asunderstood by those skilled in the art, is intended to be implied byconsistent usage of the term or phrase herein. To the extent that a termor phrase is intended to have a special meaning, i.e., a meaning otherthan that understood by skilled artisans, such a special definition willbe expressly set forth in the specification in a definitional mannerthat directly and unequivocally provides the special definition for theterm or phrase.

Embodiments herein provide for increasing at least a portion of one ormore source or drain fins of finFET devices using epitaxial (EPI)deposition/growth. Embodiments herein provide for increasing the currentdrive of a finFET by controlling the deposition of an EPI layer, e.g.,single-domain (SD) EPI layer, on the top regions of source-drain fins ofa finFET. Embodiments herein provide for controlling the lateral growthof EPI layer on source-drain fins substantially without impeding thevertical growth of EIP layer. In this manner, shorts caused byover-growth of EPI layers on densely formed fins are reduced, whilemaintaining sufficient EPI growth.

Turning now to FIG. 4, a flowchart depiction of a method for forming EPIlayer on source-drain fins for finFET devices while controlling lateralover-growth, in accordance with embodiments herein, is illustrated. Asemiconductor wafer processing system may perform an initial finFETprocessing protocol for forming source/drain fins (block 410). An oxidedeposition process may then be performed (block 420). This process maycomprise deposition of silicon oxide over the fins. In many embodiments,the fins are formed in a dense manner, wherein the small spaces betweenthe densely formed fins are filled by oxide deposition.

Subsequently, a recess process to remove the silicon oxide is performed(block 430). The recess process may comprise implementing a wet etchprocess, a SiCoNi etch process, or a combination of both, which resultsin substantial removal of silicon oxide layer. This process results inremoval of the silicon oxide from the fins while leaving silicon oxidematerial between the fins of a single finFET device, i.e., between thenarrow gap of fins of each finFET device.

A spacer nitride deposition process may then be performed (block 440).The spacer nitride deposition process comprises depositing siliconnitride over the source-drain fins of the finFET. A nitride removalprocess may then be performed (block 450). This process leave nitridespacer material (e.g., silicon nitride) between the devices, i.e., onthe outer walls for the fins of each finFET.

Subsequently, an etching process for removing the remaining siliconoxide between the fins may be performed (block 460). This process leavesthe exposed part of the fins (i.e., the portion of the fins above theSTI layer) substantially bare except for the silicon nitride remainingon the outer walls of the outer fins of each finFET.

At this point, an EPI deposition process is performed (block 470), whichresults in growth of the EPI layer in a laterally suppressed manner, asdescribed in further details below. That is, the remaining siliconnitride materials on the outer fin wall suppress the lateral and/orpartial downward vertical growth of the EPI layers on the outer portionsof the outer walls of the source-drain fins. Accordingly, EPI growth atthe top of the source-drain fins are controlled by embodiments herein,wherein lateral growth of the outer fins are limited as to preventshorts to fins or to other features of adjacent finFET devices.

FIGS. 5-6 illustrate various stylized diagrams relating to forming afinFET device, in accordance with embodiments herein. FIG. 5schematically illustrates a perspective view of a semiconductor device500, which may also be referred to as a multi-gate finFET device, sinceat least two separate channel regions may be controlled by respectiveportions of a gate electrode. In the manufacturing stage shown, thedevice 500 may comprise a substrate 501, such as a silicon substrate orany other appropriate carrier material, on which may be formed anappropriate base layer 502, which, in some illustrative embodiments, mayrepresent an insulating layer, such as a silicon dioxide layer, asilicon nitride layer, a silicon oxynitride layer and the like. Forexample, if the substrate 501 may be comprised of a substantiallycrystalline semiconductor material, the base layer 502, if provided inthe form of an insulating material, and the substrate 501 may define asilicon-on-insulator (SOI) configuration.

Moreover, a plurality of fins 510 are formed on the layer 502 andcomprise respective end portions 510E and a central portion 510C, whichis covered by a gate electrode structure 520. Furthermore, a gateinsulation material may be formed at least on sidewalls of the fins 510(not shown in FIG. 5), while a corresponding gate insulation layer maybe formed on a top surface of the fins 510 if a tri-gate transistorarchitecture is considered. In other cases, the fins 510 may be coveredby a cap layer (not shown) which may result in an insufficientcapacitive coupling to the fins 510, so that the top surface thereof mayeffectively not act as a channel region. With respect to any materialcomposition of the fins 510, it is to be appreciated that anyappropriate material, such as silicon, silicon/germanium, germanium orany other appropriate semiconductor compound may be used, depending onthe overall device requirements. Similarly, the corresponding dimensionsof the fins 510 may be selected in accordance with the design rules ofthe corresponding technology node under consideration.

FIG. 6 illustrates a stylized depiction of a cross-sectional view takenalong the section IIb of FIG. 5. As illustrated, a cap layer 512, suchas a silicon oxide or High-K HFO₂ layer and the like, may be formed onthe fins 510, and the gate electrode structure 520, which may becomprised of any appropriate material, such as polysilicon, ametal-containing material and the like, may be formed on the cap layer512 and may also extend down to the layer 502 along the correspondingsidewalls of a Fin 510 (not shown in the section of FIG. 6). Thesemiconductor device 500 as shown in FIGS. 5 and 6 may be formed on thebasis of well-established process techniques as are, for instance, alsoexplained above with reference to the device 100.

FIG. 7-19 illustrate stylized cross-sectional depictions of finFETdevices under various stage of manufacture, in accordance withembodiments herein. FIG. 7 illustrates a stylized cross-sectional viewof a set of finFETs (device 700) under manufacture, and FIG. 8illustrates a stylized cross-sectional 90 degree rotated view of the setof finFETs of FIG. 8, in accordance with embodiments herein. In someembodiments, the device 700 under manufacture may comprise a pluralityof finFET devices are formed. Referring simultaneously to FIGS. 7 and 8,the device 700 comprises a substrate layer 705 (e.g., silicon substrate,silicon germanium substrate, etc.) on which a base layer 710 is formed.Using one of various techniques (such as the techniques described withrespect to FIGS. 5-6), source-drain fins 730(a-d) are formed on the baselayer 710. Fins 730 a, 730 b, and 730 c are source-drains fins for afirst device, while fin 730 d is a source-drain fin for a second finFETdevice.

The source-drain fins 730 are be surrounded by gates 910 and 920 (FIG.8), which in one embodiment, may be dummy gates. A gate hard mask 760may be formed on the gates 910, 920. FIG. 8 also illustrates an STIlayer 720 that is formed on the substrate 705.

On top of the base layer 710 (FIG. 7), an STI layer 720 may be formed.The portions of the fins 730 that rise above the STI layer 720 areexposed, and as such, EPI layers may be grown on those portions. Whengrowing an EPI layer at the top of the fins 730, it is desirable toprevent shorts caused by over-growth of the EPI layers between fins offirst and second finFETs. It is also desirable to prevent formation of asource-drain bridge that could result from over-growth of EPI layers,which could cause a short upon the end of a gate of the finFET devices.Accordingly, embodiments herein provide for mitigating the lateralgrowth of EPI layers on the outer walls of source-drain fins borderingone finFET device to another.

Referring simultaneously to FIGS. 9 and 10, FIG. 9 illustrates astylized cross-sectional view of a set of the finFETs undergoing anoxide deposition process. and FIG. 10 illustrates a stylizedcross-sectional 90 degree rotated view of the set of finFETs of FIG. 9,in accordance with embodiments herein. An oxide deposition process isperformed. This process comprises deposition of silicon oxide over thesource-drain fins, including within spaces between the fins. The oxidematerial is deposited between the small spaces between fins 730 a, 730b, 730 c of the first device, as well as between larger spaces betweenthe border/outer fins, e.g., between fin 730 c of the first device andfin 730 d of the second device.

The source-drain fins 730 are be surrounded by gates 910 and 920 (FIG.9), which in one embodiment may be dummy gates. The oxide material 810deposited above the fins 730 and gates 910, 920 may be thick enough toleave a space 930 between the gates 910, 920 (as shown in FIG. 10), butviscous enough to fill the space between the fins 730(a-c) of the firstdevice (as shown in FIG. 9). Moreover, as shown in FIG. 8, afterdepositing the oxide layer 810, a space 750 is left between fins of thefirst device and fins of the second device.

Referring simultaneously to FIGS. 11 and 12, FIG. 11 illustrates astylized cross-sectional view of a set of the finFETs undergoing anoxide removal process, and FIG. 12 illustrates a stylizedcross-sectional 90 degree rotated view of the set of finFETs of FIG. 10,in accordance with embodiments herein. A recess process is performed tosubstantially remove the oxide material 810 (e.g., silicon oxide).

The recess process may comprise implementing a wet etch process, aSiCoNi etch process, or a combination of both. As shown in FIGS. 11 and12, the recess process removes the oxide material 810 between the gates910, 920, as well as between the border fins (fins 730 a and 730 c) ofthe first device and the border fin (fin 730 d) of the second device. Asshown in FIG. 11, after this recess process, oxide material 810 remainsbetween the fins 730(a-c) of a finFET device.

Referring simultaneously to FIGS. 13 and 14, FIG. 13 illustrates astylized cross-sectional view of a set of the finFETs undergoing anitride deposition process, and FIG. 14 illustrates a stylizedcross-sectional 90 degree rotated view of the set of finFETs of FIG. 13,in accordance with embodiments herein. A spacer nitride depositionprocess is performed on the devices 700. The spacer nitride material1210 (e.g., silicon nitride) deposited above the fins 730 and gates 910,920 may be thick enough to leave a space 1330 between the gates 910, 920(as shown in FIG. 14), but viscous enough to fill the space between thefins 730(a-c) of the first device (as shown in FIG. 13). Moreover, asshown in FIG. 12, after depositing spacer nitride 1210, a space 1230 isleft between fins of the first device and fins of the second device.

In one embodiment, the order of processes provided herein call forperforming the oxide recess process prior to performing the spacernitride deposition process. Since the oxide recess process is performedfirst, the remaining oxide between the fins 730 a-c prevent the spacernitride material 1210 from being deposited into the inner walls of thefins 730 a-c. Therefore, EPI deposition/growth can take place betweenthe inner walls for the fins 730 a-c.

Referring simultaneously to FIGS. 15 and 16, FIG. 15 illustrates astylized cross-sectional view of a set of the finFETs undergoing aspacer nitride removal process, and FIG. 16 illustrates a stylizedcross-sectional 90 degree rotated view of the set of finFETs of FIG. 15,in accordance with embodiments herein. A spacer nitride removal (e.g.,spacer etch process) may be performed for substantially removing thespacer nitride between the fins. This process removes the nitride spacermaterial 1210 from between the inner walls of the fins 730 a-c of thefirst device, as shown in FIG. 14. As shown in FIG. 16, the nitridespacer material 1210 remains in the side walls for the gates 910, 920.

Further, the nitride spacer material 1210 remains on the outside wallsof the outer fins 730 a, 730 c of the first device as wells as the fin730 d of the second device. The remaining nitride space materials 1210adjacent to the fins 730 a, 730 c and 730 d are capable of suppressingthe lateral growth and/or downward vertical growth of EPI layers grownon the outer portions fins 730 a, 730 c, 730 d. This suppression may beachieved while not suppressing vertical growth of the EPI layers on theouter portions, and not suppressing any EIP growth on the inner portionsof the fins 730 a and 730 c

Referring simultaneously to FIGS. 17 and 18, FIG. 17 illustrates astylized cross-sectional view of a set of the finFETs undergoing an EPIfill oxide recess process, and FIG. 18 illustrates a stylizedcross-sectional 90 degree rotated view of the set of finFETs of FIG. 17,in accordance with embodiments herein. In one embodiment, a wet etch, adry etch, or a combination thereof may be performed to remove theremaining silicon oxide between the fins 730.

The EPI fill oxide recess process is performed for removing oxide in amanner that an EPI layer may be deposited into the regions from whichoxide was removed. As shown in FIG. 17, EPI fill oxide recess processremoves oxide material from between the dense fins 730(a-c), leavingonly the space nitride portions on the outer walls for the outer fins730 a, 730 c. This process leaves the exposed part of the fins 730(i.e., the portion of the fins above the STI layer 720) substantiallybare except for the silicon nitride remaining on the outer walls of theouter fins 730 a, 730 c of each finFET. As such EPI layer may be formedon the fins 730 in the suppressed manner described herein.

FIG. 18 illustrates that the spacer nitride between the fins 730 and thegates 910, 920 remain after the EPI fill oxide recess process. In thismanner, EPI growth/deposition on the fins 730 is controlled such thatthe EPI formations do not cause shorts between the EPI layers and thegates, or between the EPI layer of the fins 730 a-c of a first deviceand the fin 730 d of a second device.

Referring simultaneously to FIGS. 19 and 20, FIG. 19 illustrates astylized cross-sectional view of a set of the finFETs undergoing an EPIdeposition process, and FIG. 20 illustrates a stylized cross-sectional90 degree rotated view of the set of finFETs of FIG. 19, in accordancewith embodiments herein. At the top portions of the source-drains fins730, i.e., the exposed portions of the fins 730 above the STI layer 720,EPI depositions/growth may be performed. As shown in FIG. 19, EPI layers1820 are formed on the fins 720.

In some embodiments, the EPI layers 1820 may be grown to a size of about5 nm to about 20 nm (lateral EPI width). The EPI layers 1820 may bedeposited using a chemical vapor deposition process (CVD), e.g., reducedpressure CVD (RPCVD), ultra-high vacuum CVD (UHVCVD), metal organic CVD(MOCVD), etc. The precursors for the EPI layers 1820 may comprise gasescomprising silicon (e.g., SiH₄, Si₂H₄Cl₂, Si₂H₆, Si₃H₈) and/or gasescomprising germanium (e.g., GeH₄). The partial pressures of these gasesmay be adjusted to adjust the atomic ratio of germanium to silicon. Inone embodiment, the EPI layers may be grown at 700° C., and may bedecreased to 550° C. with source gas.

The deposition of the EPI layers 1820 may be performed as a plurality ofdeposition-etch cycles to provide epitaxial layers that are moreconformal. As illustrated in FIG. 18, generally, the shape of the EPIlayers 1820 upon deposition may be generally a diamond shape immediatelyafter EPI growth. As would be appreciated by those skilled in the arthaving benefit of the present disclosure, further processing of thedevice 700 may cause the shape of the EPI formation to change from thediamond shape to a more rounded shape.

In one embodiment, the dimensions of the EIP layers (e.g., the width)may be controlled in such a manner that they are proportional torespective widths of the fins 730. The over-growth of EPI layers 1820 iscurtailed by the presence of the spacer nitride material 1210.Therefore, the lateral growth and the downward vertical growth of theEPI layer on the out fins (730 a, 730 c) and the fin 730 d may becurtailed by the presence of the nitride material 1210. Moreover, theEPI growths at the inner portions of the outer fins 730 a, 730 c andaround the inner fin 730 b are not suppressed and thus, free to grow inthe lateral and the vertical dimensions.

As indicated in FIG. 20, the growth of the EPI layers 1820 is restrictedto the regions above the fins 720 and away from the gates 910, 920 as aresult of the presence of the space nitride material 1210. Further, asshown in FIG. 18, the later growth of the EPI layers 1820 are suppressedby the presence of the spacer nitride material 1210 at the outside wallsof the outer fins 730 a, 730 c of the first device and the walls of thefin 730 d of the second device. In this manner, sufficient EPI growthtakes place in the vertical and lateral directions around the fins730(a-c), while growth in the lateral and downward directions on theouter walls of the fins 730 a, 730 c, and 730 d are restricted by thepresence of the spacer nitride material 1210. Therefore, the probabilityof shorts developing between fins of different devices and/or gates aresubstantially reduced by embodiments herein.

Subsequent processing known to those skilled in the art having benefitof the present disclosure may be performed to form a complete finFETdevice (e.g., patterning, lithography, etch, metal gate, etc.). Suchsubsequent processing steps may be used to form finFET devices thatcomprise source-drain fins that comprise EPI growth with lateralover-growth of the EPI being substantially curtailed on the outer wallsof the fins.

Turning now to FIG. 21, a stylized depiction of a system for fabricatinga semiconductor device package comprising a topside interconnectionsubstrate, in accordance with embodiments herein, is illustrated. Thesystem 2100 of FIG. 21 may comprise a semiconductor device processingsystem 2110 and a design unit 2140. The semiconductor device processingsystem 2110 may manufacture integrated circuit devices based upon one ormore designs provided by the design unit 2140.

The semiconductor device processing system 2110 may comprise variousprocessing stations, such as etch process stations, photolithographyprocess stations, CMP process stations, etc. One or more of theprocessing steps performed by the processing system 2110 may becontrolled by the processing controller 2120. The processing controller2120 may be a workstation computer, a desktop computer, a laptopcomputer, a tablet computer, or any other type of computing devicecomprising one or more software products that are capable of controllingprocesses, receiving process feedback, receiving test results data,performing learning cycle adjustments, performing process adjustments,etc.

The semiconductor device processing system 2110 may produce integratedcircuits on a medium, such as silicon wafers. More particularly, thesemiconductor device processing system 2110 produce integrated circuitshaving finFET devices that source-drain fins that comprise EPI growthwith lateral over-growth of the EPI being substantially curtailed on theouter walls of the fins, as described above.

The production of integrated circuits by the device processing system2110 may be based upon the circuit designs provided by the integratedcircuits design unit 2140. The processing system 2110 may provideprocessed integrated circuits/devices 2115 on a transport mechanism2150, such as a conveyor system. In some embodiments, the conveyorsystem may be sophisticated clean room transport systems that arecapable of transporting semiconductor wafers. In one embodiment, thesemiconductor device processing system 2110 may comprise a plurality ofprocessing steps, e.g., the 1^(st) process step, the 2^(nd) process set,etc., as described above.

In some embodiments, the items labeled “2115” may represent individualwafers, and in other embodiments, the items 2115 may represent a groupof semiconductor wafers, e.g., a “lot” of semiconductor wafers. Theintegrated circuit or device 2115 may be a transistor, a capacitor, aresistor, a memory cell, a processor, and/or the like. In oneembodiment, the device 2115 is a transistor and the dielectric layer isa gate insulation layer for the transistor.

The integrated circuit design unit 2140 of the system 2100 is capable ofproviding a circuit design that may be manufactured by the semiconductorprocessing system 2110. The integrated circuit design unit 2140 may becapable of determining the number of devices (e.g., processors, memorydevices, etc.) to place in a device package. The integrated circuitdesign unit 2140 may also determine the height of the gate fins, thedimensions of EPI growth on fins of the finFET devices, etc. Thesedimensions may be based upon data relating to drive currents/performancemetrics, device dimensions, etc. Based upon such details of the devices,the integrated circuit design unit 2140 may determine specifications ofthe finFETs that are to be manufactured. Based upon thesespecifications, the integrated circuit design unit 2140 may provide datafor manufacturing a semiconductor device package described herein.

The system 2100 may be capable of performing analysis and manufacturingof various products involving various technologies. For example, thesystem 2100 may design and production data for manufacturing devices ofCMOS technology, Flash technology, BiCMOS technology, power devices,memory devices (e.g., DRAM devices), NAND memory devices, and/or variousother semiconductor technologies.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. For example, the process steps set forth above may beperformed in a different order. Furthermore, no limitations are intendedto the details of construction or design herein shown, other than asdescribed in the claims below. It is therefore evident that theparticular embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. Accordingly, the protection sought herein is as set forth inthe claims below.

What is claimed is:
 1. A method, comprising: forming a set of fins of afirst transistor, said set of fins comprising a first outer fin, aninner fin, and a second outer fin; performing an oxide depositionprocess for depositing an oxide material upon said set of fins andwithin spaces between said fins; performing a first recess process forremoving a portion of the oxide material, leaving a portion of the oxidematerial on inside walls of said first and second outer fins; performinga spacer nitride deposition process for depositing a spacer nitridematerial upon said set of fins and on outer walls of the first andsecond outer fins; preforming a spacer nitride removal process, leavingspacer nitride material on a first portion at the outer walls of thefirst and second outer fins; performing a second recess process forremoving said oxide material from the inside walls of said first andsecond outer fins; and performing an epitaxial layer deposition processupon said set of fins and said outer walls of said first and secondouter fins, wherein any lateral over-growth of epitaxial layer on saidouter walls of said first and second outer fins is suppressed by saidspacer nitride material at the first portion, and wherein lateralovergrowth of the epitaxial layer occurs on a second portion of theouter walls of said first and second outer fins.
 2. The method of claim1, wherein forming said epitaxial layer comprises performing at leastone of a reduced pressure CVD (RPCVD), ultra-high vacuum CVD (UHVCVD),metal organic CVD (MOCVD).
 3. The method of claim 1, wherein formingsaid epitaxial layer upon comprises providing a precursor selected fromthe group consisting of SiH₄ gas, Si₂H₄Cl₂ gas, Si₂H₆ gas, Si₃H₈ gas andGeH₄ gas.
 4. The method of claim 1, wherein performing said first recessprocess comprises performing an SiCoNi etch process.
 5. The method ofclaim 1, wherein said performing said epitaxial layer deposition processfurther comprises forming said epitaxial layer upon a third outer fin ofa second transistor adjacent to said first transistor, such that saidepitaxial layer on said first outer fin does not touch said epitaxiallayer deposited on said third outer fin.
 6. The method of claim 1,wherein performing said oxide deposition process comprises depositingsilicon dioxide.
 7. The method of claim 1, wherein performing saidspacer nitride deposition process comprises depositing silicon nitride.8. The method of claim 1, wherein at least a portion of any verticalover-growth of said epitaxial layers on said outer walls of said firstand second outer fins is suppressed by said spacer nitride material.